The trend in keyboards is to add keys to match the need for access to more of the computer functions made available with modern computer chips. Hand held computers regularly employ 40 keys and desk top computers often have well over 100 as standard. Even so, keyboards have not kept pace with the proliferation of computer chip functions available in the art, literally numbering in thousands for a single standard chip. Thus as computers become more powerful and compact, keyboards are becoming more bulky and confusing. This trend, in ergonomic terms, is hardly to be considered a good one, since in order to have computers used with ease by more people it is imperative that the user/computer interface be simplified both in structure and in logic.
Keyboard U.S. Pat. No. 3,892,958--July 1, 1975 to C. C. Tung is exemplary of the trend by some manufacturers in the keyboards they offer. The objective is to reduce the number of computer keyboard keys, yet 35 keys are still used. Prefix keys (gold--f and blue--g) are added for use in activating the keyboard in alternative computer selection modes to permit the keyboard to select three different functions per key. This extends the range of a 39 key keyboard available in a Hewlett Packard Model 15C computer, for example, to make accessible more of the computer chip built-in operating functions and program modes, namely 96, but at a cost of additional keys. Still 96 functions are undoubtedly far less than the several hundred available on computer chips in the present state of the art. Thus, access to full capacities of the chips is not feasible with the prior art keyboards, and a relatively large number of keys is still required to significantly extend the keyboard capacity to select more functions available on the chip.
Furthermore, with the 39 keys (or more as required to process more powerful chips) in a hand held pocket-sized computer, the keys have to be placed so close together that it is difficult to make choices manually without fingering a wrong key. Also a sequence of reasoned selections must be made on prior art keyboards that interrupts the mental process and thereby introduces many opportunities for potential error into the key selection process.
This potential for error in manual selection of computer functions is even more pronounced whenever there are routines performed which are not indicated visibly on the keyboard in easy to identify and follow notation. Prior art keyboards have not resolved the problem of how to indicate two or more successive keystrokes necessary to complete some of the selectable functions or programs except for the aforesaid example which color codes a prefix key with a code abbreviation of the functions made accessible thereby. If complex key stroke sequences for various functions need be memorized or intermediate reference made to an instruction manual, the propensity for error is increased by the further interposition of unrelated thought processes. Thus, it has not been possible to provide access directly adjacent the keyboard keys of the necessary information for using a computer to perform several functions in many modes of operation. This is particularly true for pocket-sized computers where keyboard space is necessarily limited. Even desk-top computers which have to be programmed by mathematics and engineering oriented persons who are not expert typists are difficult for some users as they must "hunt and peck" among the more than one hundred keys which are usual on such keyboards.
The keyboard patent heretofore mentioned does provide a limited amount of flexibility to the use of keys on the keyboard as identified by visible keyboard legends. Thus the keyboard is usable in three different modes for function selection. To activate the two additional modes a manual selection of a color coded key is required such as gold (f) and blue (g) to correspond to color coded legends on the keyboard panel facing or key. While this substantially triples the number of functions available to the keyboard it requires more not fewer keys, and it requires a search of the desired function on one of three color coded legends over the keyboard face, a physical move to another part of the keyboard for the prefix keystroke for that color code and a return to the selected key for function selection. Clearly, the chances for error are great, and time taken in selection and operation is long. Furthermore, there is no way taught in the prior art for using substantially all the functions available from the computer chip with a simple keyboard having a few keys.
Present day portable computers, which already have phenomenal computing capability, can have their capability expanded still further by the use of special purpose plug-in chips which are pre-programmed to solve problems peculiar to specialized disciplines such as navigation, mechanical engineering, electrical engineering, statistics, etc.
When these "modules" are plugged in to the host computer the total computing power of even hand-held instruments is increased substantially.
An already serious ergonomics problem is compounded, however, since the user is now required to remember the increased repertoire of his instrument or refer to the instruction book and then manipulate the 35 or so keys in a manner which is not self-evident from the appearance of the keyboard. Specially printed keyboard overlay cards are of some help, but being passive they do not alter the functioning of the keys which retain the identical functions whether or not the overlay card is in place.